Im going to be straight to the point about headphone amps here. they are purely meant to reproduce the source as accurately as possible. Although some people claim their hpa's color the sound with bass mids highs or sounstage etc etc thats really not the intention of hpa's although some have used different sounding hpas to tweak the sound of their current setups more to their tastes. there are other ways to do this as well. As for your bithead, it is a relative low end HPA so you shouldnt expect much improvement over the cowon d2 especially since cowon is a very quality company whn it comes to sq i still think my x5 is my best sounding DAP. Especially if your using cheap interconnects anywhere in your rig that will affect your sound also. In order to see real sound changes youd either have to modify your cowon or amp, or swap your amp or dap for something different. or mod your akgs. Personally i havent heard the 702s but ive found the akg brand to be very neutral wih respect to sound sig. very good in all aspects of sound reproduction with no glaring weaknesses except the ones in your music. this is very typical of studio company headphones however i think akg does it best. all in all i think modding the akgs would be a waste of money as its very expensive and i think youd be better off investing in a more quality HPA.

Well just to update this, I'm going to be selling my 16gb D2 as I've got a custom made iMod coming which I'll be pairing up with the Corda 3MOVE amp (much better/more powerfull then Bithead)

Since writing this post and asking the newbie question, I've spent a lot of time on head-fi (now addicted) and have learned extensively. I've also since purchased the Essence STX to use as my home setup and the imod+3move as my mobile/almost portable setup

Thanks for your input though Malakei.. always nice to read posts from knowledgable people :)